High temperature wear has been a significant problem for engine parts such as where an exhaust valve repetitively contacts a valve seat. Most currently produced valve seats are simply made of cast iron or steel enhanced with alloying ingredients which are believed to improve hardness and wear resistance at high temperatures. However, such iron based materials without heat treatment cannot attain sufficient hardness and wear resistance to be useful as a valve seat. With heat treatment, the processing becomes undesirably expensive for modern engines.
Use of cast iron or steel valve seats has not proved entirely successful in aluminum head engines because of the uncontrollable pick up of aluminum to form brittle intermetallic materials in the valve seat. Very little research has been undertaken with the use of noniron based materials compatible with aluminum, such as copper based materials, for valve seats. Copper based materials are typically relatively soft and thus have not been considered candidates for valve seat applications.